1. Field of the Invention
The invention relates to ergoline derivatives, to processes for their preparation and to pharmaceutical compositions containing ergoline derivatives.
2. Discussion of the Background
The 1-alkylation of ergolines may be performed by reacting non-alkylated ergolines with alkyl halides in liquid ammonia in the presence of a strong base such as potassium amide (see Troxler F., Hofmann A., Helv. Chim. Acta, 40 2160 (1957)). The efficiency of this alkylation reaction is good for primary alkyl halides, but much reduced for secondary alkyl halides. Tertiary alkyl halides do not react at all but instead yield the related olefins by elimination.
The prior art has not disclosed a suitable methodology for the addition of a tertiary alkyl group to the 1 position of the ergoline molecule.